A couple sought in connection with the death of an MI6 officer may never be traced, police have conceded.
Gareth Williams from Holyhead had been on secondment to MI6 from GCHQ.
Paul Knapman adjourned an inquiry into the 31-year-old’s death as Scotland Yard detectives wait for the results of a fresh round of forensic tests.
Mr. Williams’ body was discovered naked in a padlocked holdall in his Pimlico flat last August.
Detective Chief Inspector Jackie Sebire admitted the likelihood of tracing a Mediterranean couple seen at Mr Williams’s home weeks before his death is diminishing.
Counter-terrorism officers have interviewed “in the region of 40” of the expert codebreaker’s colleagues at MI6 and GCHQ, Westminster Coroner’s Court heard.
A number of those interviewed could be called to give evidence anonymously at Mr. Williams inquest.
She said it is “very unusual” for two teams of officers to be working on a suspicious death inquiry, but said the victim’s secretive occupation was the reason.
Speaking about forensic tests, she added: “We have done a phased submission of tests to the laboratory. We are still waiting for some outstanding tests that went out before Christmas.”
After a 10-minute hearing, Dr Knapman adjourned the inquest until Thursday March 31, but said it is not known whether it will go ahead then.